a(n) = (binomial(2*p,p)-2)/p^2 where p = prime(n).

A060842

a(n) = (binomial(2*p,p)-2)/p^2 where p = prime(n).

Terms

    a(0) =1a(1) =2a(2) =10a(3) =70a(4) =5830a(5) =61542a(6) =8074762a(7) =97909318a(8) =15564141262

External references